This application claims priority to Japanese Patent Application No. 2002-257728 filed Sep. 3, 2002, which application is herein expressly incorporated by reference.
The present invention relates to an electrical conductor assembly and, more particularly, to an electrical conductor assembly, including a bus bar, arranged as an internal circuit in an electrical connection box, such as a junction box or the like, to be mounted on an automobile. The bus bar is made of a much recyclable material.
Heretofore, bus bars have been produced by being punched out of an electrical conductive material. The bus bars are contained as internal circuits in an electrical connection box such as a junction box or the like.
For convenience of explanation, a conventional electrical conductor assembly will be described by referring to FIGS. 7 and 8. FIG. 7 is an exploded perspective view of a conventional electrical connection box. FIG. 8 is an explanatory view that illustrates problems in the conventional electrical connection box.
As shown in FIG. 7, an electrical connection box 1 includes a casing with an upper casing member 2 and a lower casing member 5. Bus bars 4 and insulation plates 3 are laminated alternately on each other in the casing. An end of each bus bar 4 is bent to form a tab 4a. The tabs 4a penetrate a connector containing section 2a in the upper casing 2, a fuse containing section 2b, and a relay containing section 2c directly or through intermediate terminals. The tabs 4a are connected to a connector C coupled to a wire harness W/H, a fuse F, and a relay R.
The bus bars 4, constituting the internal circuits, are made of a copper-based metal plate having high electrical conductivity. After punching the copper-based metal plate into bus bars 4, having desired circuit configurations, a desired end of each bus bar 4 is bent to form a tab 4a. 
Recently, requirements to enhance the recyclability of junked automobiles have been instituted. Iron makes up the highest percentage of an automobile. When a junked automobile is thrown into an incinerator to recover and recycle iron, it is required that a mixing rate of copper to iron should be less than 0.1%. This prevents the iron from being denatured due to a reaction with the copper.
Since the bus bars 4 are made of copper-based metal plate, as described above, it is preferable to remove the bus bars 4 from the car body upon disassembly of the automobile. The bus bars 4 are separated from the car body made of an iron-based metal. However, the electrical connection box must be disassembled in order to remove the bus bars from the electrical connection box 1. This work requires extensive manpower and is not practical.
To avoid interference with iron recovery, from a practical recycling standpoint, the bus bar should be selected from an aluminum-based metal material that will not denature the iron reaction.
However, as shown in FIG. 8, there is a problem in the following case. A bus bar 4xe2x80x2 is made of an aluminum-based metal. An end of the bus bar 4xe2x80x2 is bent to form a tab 4axe2x80x2. A press contact slot 4b is formed in the tab 4axe2x80x2. A terminal T of a fuse or a relay, or a male terminal T contained in a connector is forcedly pushed into the press contact slot 4b. 
In this type of press contact connection, the press contact slot 4b is a narrow U-shaped groove having a width S smaller than a thickness of a terminal T. Although the terminal T widens the press contact slot, opposite wings of the tab return to their original positions by their elastic recovery forces, thereby forming a stable press contact connection.
Heretofore, since the bus bar having the tab is made of a copper-based metal plate having elasticity, a stable press contact connection can be obtained. However, since the aluminum-based metal has no elasticity, wings 4c on the opposite sides of the press contact slot 4b cannot return from the widened positions to the original positions. Accordingly, this does not exert a desired contact pressure.
In view of the above problem, an object of the present invention is to provide an electrical conductor assembly where bus bars are made of an aluminum-based metal plate in order to enhance recyclability of the automobile. Also, a tab formed on the bus bar is not deformed.
In order to achieve the above object, the present invention is directed to an electrical conductor assembly adapted to be contained in an electrical connection box to be mounted on an automobile. The assembly includes a bus bar produced by punching an aluminum-based metal plate into a desired circuit configuration. The bus bar includes a press contact tab formed by bending the end of the bus bar. A tab cover, for reinforcement, encloses an exterior of the press contact tab. The press contact tab has a press contact slot that extends from a distal end of the tab to a proximal end of the tab. The tab cover is made of an iron-based metal plate having elastic characteristics. The tab cover is provided in opposed sidewalls with insertion grooves that communicate with the press contact slot in the press contact tab.
Since the bus bar is made of an aluminum-based metal, the mixing rate of copper to iron can be reduced. This reduces the problem upon recovery of iron during recycling of a car body in the prior art. It is also possible to enhance recyclability for junked automobiles. In addition, the bus bars made of aluminum-based metal have rust-resistance characteristics and good workability and help to provide a lightweight electrical connection box.
The tab cover made of an iron-based metal plate, such as a stainless steel plate or the like having elasticity, is mounted on the press contact tab of the bus bar made of an aluminum-based metal plate. An elastic recovery force is exerted in the tab cover. This force will return the wings on the opposite sides of the press contact slot in the tab from deformed positions, upon press contact connection, to the original positions while maintaining a desired contact pressure between the mating terminal and the wings of the tab.
Furthermore, the tab cover encloses the press contact tab. This reinforces the tab to prevent the press contact tab from buckling under excessive pushing force.
The tab cover is preferably made of a stainless steel plate having high elasticity. Since the stainless steel plate and the aluminum plate are different kinds of metals, no electric erosion will occur between the plates. Accordingly, the stainless steel plate is most suitable.
The tab cover is made of a stainless steel plate. The bus bar may be contained in the electrical connection box after the tab cover is fixed on the press contact tab. Alternatively, the press contact tab may engage the tab cover that is fixed on the electric connection box beforehand, when the bus bar is contained in the electric connection box.
If the tab cover includes a locking piece that passes through and engages with a locking aperture formed in the electrical connection box, it is possible, beforehand, to attach the tab cover to the box. It is also possible, beforehand, to attach the tab cover to the box with the press contact tab mounting the tab cover.
The press contact tab is provided with a locking pawl. The tab cover has a locking piece that engages the locking pawl. The tab cover is locked on the press contact tab. This prevents the tab cover from coming out from the tab. A locking piece on the tab cover may be used as a common locking piece for the box. The tab cover is formed into a rectangular parallelepiped tube that fits closely around the exterior of the press contact tab.
The press contact tab includes wide surfaces including the press contact slot and narrow end surfaces arranged perpendicular to the wide surfaces. The tab cover is provided on sidewalls opposed to the narrow end surfaces of the tab with arcuately and inwardly expanded spring sections. The expanded spring sections elastically clamp the narrow end surfaces of the tab with each other to bias the tab so as to approach wings on opposite sides of the press contact slot.
The spring sections are further provided on the tab cover. The tab cover is elastic and is made of the iron-based metal. The spring sections bias the wings on the opposite sides of the press contact slot to approach each other. Accordingly, it is possible to surely maintain a press contact connection, even if the press contact tab is made of a non-elastic aluminum-based metal plate.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.